1. Field of the Invention
The invention relates to a process for producing metal parts in accordance with the principle of squeeze, or forge, casting approximately the amount of liquid metal required for one part being introduced into a permanent mold and being displaced therein by means of an upper die with the part to be produced being formed.
2. Prior Art
Such processes have numerous advantages because of the combination of casting and pressing, reported on by J. R. Franklin and A. A. Das in "Squeeze casting--a review of the status", British Foundryman", No. 3, 1977, 1984, pages 150 to 152. In principle, these processes provide for the liquid metal, once introduced into the usually preheated permanent mold, to undergo a slight cooling before the upper die is introduced. During this process the liquid metal is displaced, any solidification thereof in the mold being avoided until the final forming of the part is complete. The lowering-in pressure is then maintained while the liquid metal solidifies, after which the upper die is withdrawn and the part removed from the mold. Maintenance of the pressure during solidification allows good filling of the mold while avoiding shrinkage or blowholes and gas pockets. However, the structure does not differ substantially from the cast structure.